The impact of capnography monitoring among children and adolescents in the postanesthesia care unit: a randomized controlled trial.

BACKGROUND: Pulse oximetry does not reliably recognize respiratory depression, particularly in the presence of supplemental oxygen. Capnography frequently detects hypoventilation and apnea among children recovering from anesthesia. Although children are routinely monitored with capnography during anesthesia, reducing the rate of adverse events, it is not routinely used in the postanesthesia care unit (PACU), where patients remain at risk for respiratory depression. AIM: We hypothesized that children monitored with capnography would have more frequent staff interventions and fewer adverse events than children monitored with pulse oximetry alone. METHODS: Otherwise healthy children of age 1-20 years undergoing general anesthesia for elective surgery were eligible for enrollment upon entering the pediatric PACU. Subjects were randomized as to whether PACU staff could view the capnography monitor (intervention group) or not (control group). All children received standard monitoring with pulse oximetry. Vital signs and patient interventions were recorded every 30 s by a portable monitor or a research associate. RESULTS: Data from 201 children were analyzed. The rates of hypopneic hypoventilation [5% (95% CI: 2-8%) per minute vs 1% (95% CI: -1% to 3%) per minute, difference 4% (95% CI: 0.2-8%) per minute; P = 0.04] and apnea [11% (95% CI: 8-14%) per minute vs 1.5% (95% CI: -2% to 5%) per minute, difference 9% (5-14%) per minute; P < 0.001] decreased significantly faster in our intervention group as compared to the control group. The rates of bradypnea decreased faster in our control group [5% (95% CI: 2-8%) per minute vs 1% (95% CI: 0-4%) per minute, difference 4% per minute, 95% CI: 0-9%; P = 0.05]. Rates of respiratory events over time between groups were affected by the presence or absence of interventions. There were no differences in rates of hypoxemia between groups over time. CONCLUSIONS: Children monitored with capnography have different rates of adverse respiratory events over time than children monitored solely with pulse oximetry. The addition of capnography improved the efficacy of staff interventions, however did not impact rates of oxygen desaturation.

Respiratory depression detected by capnography among children in the postanesthesia care unit: a cross-sectional study.

BACKGROUND: Children are at risk for respiratory depression while recovering from anesthesia. Currently, monitoring children in the postanesthesia care unit (PACU) with pulse oximetry is recommended. However, pulse oximetry does not reliably recognize hypoventilation or apnea, particularly in the presence of supplemental oxygen. Capnography is a sensitive monitor of ventilation that is not often used in the PACU. AIM: To determine the frequency of hypoventilation and apnea as detected by capnography among children in the PACU. METHODS: In a cross-sectional study, capnography monitoring was applied to healthy children of age 1-17 years in the PACU of a tertiary care hospital. Staff was blinded to the capnography monitor; alarms were disabled. Staff provided routine care and monitoring with pulse oximetry to all patients. Vital signs, patient interventions, and medication administration were recorded by a research assistant every 30 s until all monitoring was discontinued by staff. Outcome measures included frequency of hypoventilation and apnea as measured by capnography and oxygen desaturations as measured by pulse oximetry, as well as staff interventions for these events. RESULTS: Data from 194 children were analyzed. Capnography detected hypoventilation or apnea in 45.5% (95% CI 38.5%, 52.5%) of patients. Oxygen desaturations occurred in 19% (95% CI 13%, 24%) of patients. Interventions occurred in 9% (95% CI 5%, 13%) of patients. Patients who received narcotic medications were more likely to experience hypoventilation (OR 2.3, 95% CI 1.02, 5.3) and apnea (OR 2.7, 95% CI 1.1, 7). Hypoventilation was seen more often among children who received supplemental oxygen (OR 3.1, 95% CI 1.1, 12). CONCLUSIONS: Hypoventilation and apnea are common among children in the PACU; however, few interventions occur to address these events. Routine monitoring with capnography may improve recognition of respiratory depression and enhance patient safety in the PACU.

Nausea and vomiting after surgery: it is not just postoperative.

PURPOSE OF REVIEW: The purpose of this review is to highlight postoperative nausea and vomiting (PONV), to discuss why it occurs, how it might be prevented and then how it can be treated. RECENT FINDINGS: PONV/postdischarge nausea and vomiting (PDNV) is a problem that patients identify as one of the worst, if not the worst problem that can occur after surgery. Therapy is not perfect, yet there are anaesthesia techniques that can help minimize the problem and drugs that can be used both to prevent and also treat the problem once it occurs. There is a genetic basis for why some people experience PONV/PDNV more than others and also why treatment for some is better than others. SUMMARY: It is easy to turn the vapourizer dial, but that is a part of the problem. Not everyone reacts the same to drugs. Although PDNV is not as well characterized as PONV, at the very least, avoid an anaesthetic that may make PONV/PDNV worse and be aggressive in treating the problem.

Residual sleepiness after N2O sedation: a randomized control trial [ISRCTN88442975].

BACKGROUND: Nitrous oxide (N2O) provides sedation for procedures that result in constant low-intensity pain. How long do individuals remain sleepy after receiving N2O? We hypothesized that drug effects would be apparent for an hour or more. METHODS: This was a randomized, double blind controlled study. On three separate occasions, volunteers (N = 12) received 100% oxygen or 20% or 40% N2O for 30 min. Dependent measures included the multiple sleep latency test (MSLT), a Drug Effects/Liking questionnaire, visual analogue scales, and five psychomotor tests. Repeated measures analysis of variance was performed with drug and time as factors. RESULTS: During inhalation, drug effects were apparent based on the questionnaire, visual analogue scales, and psychomotor tests. Three hours after inhaling 100% oxygen or 20% N2O, subjects were sleepier than if they breathed 40% N2O. No other drug effects were apparent 1 hour after inhalation ceased. Patients did not demonstrate increased sleepiness after N2O inhalation. CONCLUSION: We found no evidence for increased sleepiness greater than 1 hour after N2O inhalation. Our study suggests that long-term effects of N2O are not significant.

Sleep tendency as a measure of recovery after drugs used for ambulatory surgery.

BACKGROUND: Although tests of psychomotor function indicate that drug effects after ambulatory anesthesia are short-lived, patients often feel washed out for long periods of time. Among the psychomotor tests that measure different motor and cognitive functions, none directly measures sleepiness or alertness. The authors hypothesized that sleepiness, measured by a sleep latency test, would be a more sensitive indicator of drug effect after an anesthetic than psychomotor tests. The second objective was to determine a sedation regimen that produced the least residual effect. METHODS: On four separate occasions, volunteers (N = 12) received an injection of propofol 2.5 mg/kg; propofol 2.0 mg/kg and fentanyl 2 microg/kg; propofol 2.0 mg/kg and midazolam 2 mg/70 kg; or midazolam 0.07 mg/kg and fentanyl 2 microg/kg. Dependent measures included the multiple sleep latency test (MSLT), Maddox Wing and digit symbol substitution tests, auditory and visual reaction times, and a divided attention task. RESULTS: The multiple sleep latency test demonstrated sleepiness up to 4 h after injection, and in some patients, sleepiness continued up to 8 h afterward. Psychomotor function was impaired only at 2 h after injection of the drug combination. CONCLUSION: The multiple sleep latency test may be a more sensitive measure of a drug's effect than other tests of psychomotor function. For up to 8 h after an injection of midazolam and fentanyl, patients must consider driving or operating heavy machinery unsafe activities.